A trucking company determined that the distance traveled per truck per year is normallydistributed, with a mean of 30 thousand miles and a standard deviation of 10 thousand miles. Complete parts(a) through(d) below.

a. What proportion of trucks can be expected to travel between 16 and 30 thousand miles in ayear?

The proportion of trucks that can be expected to travel between 16 and 30 thousand miles in a year is

(Round to four decimal places asneeded.)

b. What percentage of trucks can be expected to travel either less than 20 or more than 50 thousand miles in ayear?

The percentage of trucks that can be expected to travel either less than 20 or more than 50 thousand miles in a year is

%.

(Round to two decimal places asneeded.)

c. How many miles will be traveled by at least 70% of thetrucks?

The number of miles that will be traveled by at least 70% of the trucks is

miles.

(Round to the nearest mile asneeded.)

d. What are your answers to parts(a) through(c) if the standard deviation is 8 thousandmiles?

If the standard deviation is 8 thousandmiles, the proportion of trucks that can be expected to travel between 16 and 30 thousand miles in a year is

(Round to four decimal places asneeded.)

If the standard deviation is 8 thousandmiles, the percentage of trucks that can be expected to travel either less than 20 or more than 50 thousand miles in a year is %.

(Round to two decimal places asneeded.)

If the standard deviation is 8 thousandmiles, the number of miles that will be traveled by at least 70% of the trucks is

miles.

(Round to the nearest mile asneeded.)